my $w = Wibble->new( thingies => [ 'this', 'that' ]);

print join(", ",$w->list_thingies())."\n";
# prints "this, that"

# here's the bit that we just made work
$w->add_thingies('another');

print join(", ",$w->list_thingies())."\n";
# prints "this, that, another"